JP3785259B2 - Pulley unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulley unit including a one-way clutch. This pulley unit can be mounted on an auxiliary machine driven via a belt from a crankshaft of an engine such as an automobile. Examples of the auxiliary machine include an automobile alternator, an air conditioner compressor, a water pump, and a cooling fan.
[0002]
[Prior art]
Various auxiliary machines mounted on an automobile engine are driven via a belt by a crankshaft of the engine. Here, in the case of, for example, an alternator among auxiliary machines, when the crankshaft is connected so as to rotate synchronously with the crankshaft of the engine, the power generation capacity of the alternator is reduced when the rotation speed of the crankshaft is reduced.
[0003]
Therefore, the applicant of the present application considers that the alternator has a built-in one-way clutch, and when the rotation speed of the crankshaft decreases, the rotation of the alternator rotor is continued by its inertial force to increase the power generation efficiency. ing. That is, a one-way clutch is interposed between the pulley and the rotor of the alternator, and the one-way clutch is locked (power transmission state) and free (power transmission cut-off state) according to the rotational difference between the pulley and the rotor. And the power is transmitted or disconnected between the pulley and the rotor. Roller bearings are arranged on both sides of the one-way clutch in order to make the relative rotation of the pulley and the rotor smooth and to bear the load. Note that the fitting interference between the pulley, the one-way clutch, and the rolling bearing is set to be substantially the same.
[0004]
[Problems to be solved by the invention]
By the way, in the above conventional example, when the pulley is rotationally driven by a belt wound around the outer periphery thereof, a radial load from the belt acts on the one-way clutch and the rolling bearings on both sides thereof from the pulley. In such a situation of use, the radial load from the belt described above increases the interference between the pulley and the outer ring of the one-way clutch, and the outer ring of the one-way clutch tends to be distorted radially inward. As a result, the radial dimension of the wedge-shaped space provided at several circumferential positions of the one-way clutch is reduced, so that the rollers are displaced to the free side, and as a result, the wedge angle of the wedge-shaped space is likely to be reduced. . If the wedge angle becomes smaller than the specified lower limit value, the one-way clutch will not function normally, for example, the rollers of the one-way clutch remain locked and become free.
[0005]
Usually, the belt winding form around the pulley is partially wound around the required angular range on the circumference of the pulley, so that the distortion of the outer ring described above does not occur evenly over the entire circumference but occurs partially. For this reason, it is considered that some of the plurality of rollers included in the one-way clutch cause the above-described problems.
[0006]
In addition, conventionally, it is necessary to set a large interference fit between the pulley, the one-way clutch, and the rolling bearing so that the vibration does not cause the one-way clutch or the rolling bearings on both sides to come off from the pulley due to vibration. However, if this interference is large, the radial dimension of the wedge-shaped space is reduced, the wedge angle is reduced, and the one-way clutch does not function normally. For this reason, it has been difficult to reliably prevent the interference between the pulley and the one-way clutch.
[0007]
Therefore, an object of the present invention is to stabilize the long-term operation of a one-way clutch or a rolling bearing in a pulley unit including a one-way clutch.
[0008]
[Means for Solving the Problems]
In the pulley unit of the present invention, a one-way clutch is interposed in the middle of the annular space between a concentrically arranged pulley and a shaft body, and rolling bearings are provided on both axial sides of the one-way clutch. Are formed on both sides in the axial direction of the outer ring of the one-way clutch. The overhangs reach the outer end surface in the axial direction of the rolling bearing. When the outer ring of the one-way clutch is bulged outward in the radial direction by the fitting, the fitting interference between the region corresponding to the clutch function part of the one-way clutch and the pulley is the both overhangs. It is set smaller than the fitting interference between the part and the pulley.
[0013]
In the pulley unit of the present invention, the fitting interference between the one-way clutch and the pulley is set smaller than the fitting interference between the pulley support rolling bearing and the pulley. When the belt is driven to rotate, the radial load from the belt mainly acts on the rolling bearings on both sides in the axial direction, not on the one-way clutch. For this reason, the region corresponding to the clutch function portion in the outer ring of the one-way clutch is not distorted, and the wedge angle of the wedge-shaped space of the one-way clutch is kept unchanged.
[0014]
Moreover, the fitted tanning filtration the pulley and the one-way clutch and the rolling bearings, can be set by adjusting the tightening white during press fit of the bearing rising rolling, advantageously it is not necessary to use extra components and processing It is.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on the embodiment shown in FIGS.
[0017]
1 to 6 relate to one embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a pulley unit, FIG. 2 is a sectional view taken along line (2)-(2) in FIG. 1, and FIG. FIG. 4 is a sectional view taken along line (3)-(3) in FIG. 1, FIG. 4 is a developed plan view showing a part of the one-way clutch, and FIG. 5 is a fitting between the outer ring of the one-way clutch and the rolling bearing. FIG. 6 is an explanatory view showing the situation, and FIG. 6 is an explanatory view showing an undesirable phenomenon of the one-way clutch.
[0018]
The illustrated pulley unit A includes a pulley 1 and a shaft body 2 arranged concentrically, a one-way clutch 3 interposed in an annular space between the pulley 1 and the shaft body 2, and the annular space. Two rolling bearings 4 and 4 are provided on both axial sides of the one-way clutch 3.
[0019]
A wavy belt winding groove is formed on the outer periphery of the pulley 1, and the pulley 1 is driven to rotate through a belt B by a crankshaft of an automobile engine, for example. The shaft body 2 is made of a sleeve-like member, and is fixed to an input shaft (for example, a rotor of an alternator) of an auxiliary machine of an automobile, although not shown.
[0020]
The one-way clutch 3 includes an inner ring 10 provided with a flat key-shaped cam surface 10a at several circumferential positions on the outer peripheral surface, and overhang portions 11a and 11a for mounting the rolling bearings 4 and 4 on both ends in the axial direction. A formed outer ring 11, a cage 12 having pockets 12a that are formed to penetrate in and out of the radial direction corresponding to the cam surface 10a, and a plurality of rollers 13 that are housed one by one in each pocket 12a of the cage 12. A coil spring 14 having a substantially rectangular cross section is housed in each pocket 12a of the cage 12 and presses the rollers 13 toward the narrow side (lock side) of the wedge-shaped space between the cam surface 10a and the inner peripheral surface of the outer ring 11. And. A protrusion 12b with a narrowed base is integrally formed on the inner wall surface of the pocket 12a of the cage 12, and one end in the axial direction of the coil spring 14 is locked and fitted to the narrowed part of the base of the protrusion 12b. By receiving the inner periphery of the coil spring 14 at the outer periphery of the projection 12b, the coil spring 14 is prevented from being distorted during compression. In addition, a slit-shaped recess 10b that opens toward the shaft end and opens radially inward and outward is formed on one end surface in the axial direction of the inner ring 10 of the one-way clutch 3. Are provided with convex portions 12c that are press-fitted into the concave portion 10b from the axial direction, respectively, and the circumferential movement of the cage 12 is sealed by press-fitting between the concave portion 10b and the convex portion 12c. Yes. Moreover, the convex part 12c is pinched | interposed from the axial direction by the back wall surface of the recessed part 10b, and the end surface of the inner ring | wheel 16 of the one rolling bearing 4 arrange | positioned at the opening side of the recessed part 10b, and, thereby, the retainer 12 The movement in the axial direction is sealed.
[0021]
Each of the two rolling bearings 4 and 4 includes a general deep groove type ball bearing having an inner ring 16, an outer ring 17, a plurality of balls 18, and a cage 19, and an axial outer end between the inner and outer rings 16 and 17. The seal member 20 is mounted only on the side. The two sealing members 20 close the annular space in which the one-way clutch 3 and the rolling bearings 4 and 4 are disposed.
[0022]
In this embodiment, in the outer ring 11 of the one-way clutch 3, the area corresponding to the clutch function part, that is, the intermediate area excluding the overhanging parts 11a and 11a at both ends, and the interference of the pulley 1 is the two overhanging parts. 11a, 11a and the pulley 1 are set smaller than the fitting margin. In order to establish this relationship, specifically, as shown in FIG. 5, the inner diameter dimensions R1 and R1 of the both overhang portions 11a and 11a of the outer ring 11 are set to the outer diameter dimensions R2 and R2 of the rolling bearings 4 and 4, respectively. The rolling bearings 4 and 4 are press-fitted into both overhang portions 11a and 11a. As a result, both the overhanging portions 11a and 11a bulge outward in the radial direction, and a necessary gap is formed between the pulley 1 and the axial intermediate region of the outer ring 11, as shown in FIG. Will be. In FIG. 1, the gap is exaggerated.
[0023]
Next, the operation of the pulley unit A will be described. In short, when the rotational speed of the pulley 1 becomes relatively higher than that of the shaft body 2, the roller 13 of the one-way clutch 3 is rolled to the narrow side of the wedge-shaped space and becomes locked. 2 and rotate together. However, when the rotational speed of the pulley 1 is relatively slower than that of the shaft body 2, the rollers 13 of the one-way clutch 3 are rolled to the wide side of the wedge-shaped space and become free. The transmission of the rotational power to 2 is cut off, and the shaft body 2 continues to rotate only with the rotational inertia force.
[0024]
If such a pulley unit A is used for an alternator, the rotation of the alternator rotor is maintained at a high frequency regardless of the rotational fluctuation of the crankshaft of the engine that is the driving source of the belt B, thereby improving the power generation efficiency. Can be increased. That is, when the rotation speed of the crankshaft increases, the one-way clutch 3 is locked to rotate the shaft body 2 synchronously with the pulley 1, while when the rotation speed of the crankshaft decreases, the one-way clutch 3 is in a free state, and the shaft 2 may be continuously rotated by its own rotational inertia force regardless of the deceleration of the pulley 1.
[0025]
In such a use form, the tension of the belt B is always applied to the pulley unit A, and a radial load is always applied to the pulley 1, but as described above, the pulley 1 and the one-way clutch 3 is set to be smaller than the fitting margin between the pulley 1 and the rolling bearings 4, 4, so that the radial load from the belt B is not applied to the one-way clutch 3, This mainly acts on the rolling bearings 4 and 4 on both axial sides. As a result, the region corresponding to the clutch function part in the outer ring 11 of the one-way clutch 3 is not distorted radially inward, and the wedge angle of the wedge-shaped space of the one-way clutch 3 is kept unchanged. Therefore, it becomes possible to guarantee the stabilization of the function of the one-way clutch 3, for example, it becomes possible to keep the behavior of the roller 13 of the one-way clutch 3 locked and free. Incidentally, when the fitting interference between the pulley 1 and the one-way clutch 3 and the rolling bearings 4 and 4 is set to be the same, as shown by the broken line in FIG. The axial intermediate region of the outer ring 11 of the directional clutch 3 is distorted inward in the radial direction, whereby the roller 13 is displaced to the free side, and the wedge angle of the wedge-shaped space is reduced from θ1 to θ2, Problems such as those described in the conventional example are likely to occur.
[0026]
In addition, this invention is not limited only to the said embodiment, Various application and deformation | transformation can be considered.
[0027]
(1) FIGS. 7 and 8 show another embodiment of the present invention. In the embodiment of FIG. 7, on the outer peripheral surface of the outer ring 11 of the one-way clutch 3, the region corresponding to the clutch function portion of the one-way clutch 3, that is, the intermediate region excluding the overhang portions 11 a and 11 a, A circumferential groove 11b that forms a required gap is provided. On the other hand, in the embodiment of FIG. 8, the outer ring of the one-way clutch 3 is located on the inner peripheral surface of the pulley 1 in the region corresponding to the clutch function portion of the one-way clutch 3, that is, in the intermediate region excluding the overhang portions 11 a and 11 a. 11 is provided with a circumferential groove 1a that forms a required gap. In these embodiments, as in the above embodiment, the radial load applied to the pulley 1 is not borne on the one-way clutch 3, but is borne on the rolling bearings 4 and 4 on both sides of the one-way clutch 3. Therefore, the function stabilization of the one-way clutch 3 can be guaranteed. Further, in these embodiments, it is not necessary to apply an excessive stress to any part.
[0028]
(2) In the above embodiments, the coil spring 14 is used as an example of the elastic member of the one-way clutch 3. However, various leaf springs, elastic pieces, and the like can be used instead.
[0029]
(3) In each of the above embodiments, an example is given in which the cam surface 10a of the one-way clutch 3 is formed on the inner ring side, but the present invention can also be applied to those provided on the outer ring side. However, in the case of the above embodiment, it is suitable for use at high speed rotation, such as preventing the roller from being unnecessarily removed from the locked position by centrifugal force even in the high speed rotation range.
[0030]
(4) In each of the above-described embodiments, the outer ring 11 of the one-way clutch 3 is provided with the overhang portions 11a and 11a on both sides in the axial direction, and the rolling bearings 4 and 4 are fitted to the overhang portions 11a and 11a. However, the present invention can also be applied to a structure in which the rolling bearings 4, 4 are directly fitted to the pulley 1 without providing the overhang portions 11 a, 11 a on the outer ring 11. In this embodiment, the one-way clutch 3 can be prevented from coming off in the axial direction by sandwiching the one-way clutch 3 from the left and right with the press-fitted rolling bearings 4 and 4.
[0031]
【The invention's effect】
In the present invention , in a situation where an excessive radial load is applied to the pulley, the radial load is mainly applied to the rolling bearings on both axial sides thereof, not to the one-way clutch. Yes. As a result, it is possible to avoid distortion of the region corresponding to the clutch function portion in the outer ring of the one-way clutch, so that the wedge angle of the wedge-shaped space of the one-way clutch can be kept unchanged, and the one-way clutch can be Can function normally. As a result, the pulley unit can be greatly improved in reliability.
[0032]
In addition, by adjusting the interference fit of the rolling bearing , the interference fit between the pulley and the one-way clutch and the rolling bearing is set, which eliminates the need for extra parts and processing and contributes to cost reduction. .
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a pulley unit according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line (2)-(2) in FIG. FIG. 4 is a developed plan view showing a part of the one-way clutch. FIG. 5 is an explanatory diagram showing a fitting state between the outer ring of the one-way clutch and the rolling bearing. FIG. 7 is a longitudinal sectional view of a pulley unit according to another embodiment of the present invention. FIG. 8 is a longitudinal sectional view of a pulley unit according to another embodiment of the present invention.
A Pulley unit B Belt 1 Pulley 2 Shaft 3 One-way clutch 4 Rolling bearing 11 One-way clutch outer ring 13 One-way clutch roller

Claims (1)

Axially intermediate the one-way clutch definitive in the annular space between the pulley and the shaft are concentrically arranged is interposed, and the rolling bearing respectively on both sides in the axial direction of the one-way clutch is interposed, the A pulley unit in which overhang portions are formed on both sides in the axial direction of the outer ring of the one-way clutch so as to reach the outer end surface in the axial direction of the rolling bearing ,
A region corresponding to the clutch function portion of the one-way clutch and the pulley in the outer ring of the one-way clutch are formed by causing the both overhang portions to bulge radially outward by press-fitting of the rolling bearings. The pulley unit is characterized in that a fitting interference between the protruding portion and the pulley is set smaller than a fitting interference between the both protruding portions and the pulley.

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